is it possible to configure a Cyclone device connected to a shared serial configuration bus using the nCE signal as DCLK enable? I would like to configure it from a SecureDigital card using Passive Serial mode and an external microcontroller responsible for generating DCLK and SD protocol-specific communication with the card. The configuration should be as fast as possible, so I don't want to implement two separate data channels (SD => MCU and MCU => FPFA), but to connect SD.MISO to FPGA.DATA0 and SD.CLK to FPGA.DCLK and then simply generate the clock signal using the MCU. But using this way I can read only a sector from the card, then I must prepare the next sector and so on. This setup requires communication with the card and, obviously, Cyclone should not read configuration stream then. Can I set nCE to 1, do the necessary sector setup,then set it back to 0 and send the next part of the stream?
Best regards Piotr Wyderski